One week after offering a clinic in resilience in their biggest regular-season comeback win in 15 years, the Niners offered a lesson in ruthlessness as they bludgeoned Tampa Bay while exhorting the Bucs to match the home team’s intensity.

A year after they left Candlestick with a 21-0 win, the Bucs (3-2), self-dubbed “the West Coast Killers,” exited as West Coast road kill. The Niners won by their largest margin in 24 years while serving notice that their streak of eight non-winning seasons might end in Jim Harbaugh’s first season.

At 4-1, the 49ers, two victories away from matching last year’s win total, are off to their best start since 2002 and have won three consecutive games for the first time since 2006.

“It might be surprising to the outside,” left tackle Joe Staley said, “but it’s part of the culture that Harbaugh is instilling. We don’t care about what anyone says on the outside. If they respect us. If they like the way we play, if they don’t like the way we play. It’s all about the guys in this locker room and believing in one another. That’s what we’re doing.”

Tight end Delanie Walker said Harbaugh has made the previously sad-sack 49ers a “civilized team,” pushing them to do everything from tucking in their shirts to watching extra video.

That attention to detail was on display Sunday as San Francisco had one turnover (just its fourth in five games), committed three penalties and turned three takeaways into three touchdowns.

The nearly flawless performance began, fittingly, with Alex Smith’s 26-yard pass to Walker that gave the Niners a 7-0 lead less than five minutes into the game. The throw, lofted between three defenders, was so exquisite that Walker gave the ball to Smith, acknowledging his perfectly placed toss.

“I was shocked,” Smith said. “I didn’t know what he was doing with it, to be honest with you.”

It was perhaps the only time Smith looked befuddled Sunday. He completed 11 of 19 passes for 170 yards with three touchdowns and no interceptions, adding second-half scoring passes of 23 and 14 yards to tight end Vernon Davis. Smith, who had a 127.2 quarterback rating Sunday, has had a passer rating over 100 in back-to-back games for the first time in a career that began in 2005.

“When I talk about coach Harbaugh and the staff, I talk about it being all ball, and I mean that in a great way,” Smith said. “But that’s what it is. It’s all football. The focus is on details. The focus is on football. The focus is on teaching.”

For his part, running back Frank Gore (20 carries, 125 yards, TD), who had his second straight 100-yard game, said Smith’s solid play has forced defenses to take the focus off him. Gore averaged 49.3 yards and 2.5 yards a carry in the season’s first three games.

Gore, who was excited during training camp about playing in Harbaugh’s offense, was giddy in the postgame locker room.

“You can’t do anything with eight or nine men in the box,” Gore said. “But my man Alex is doing a great job throwing the ball down the field. My receivers are making great catches. Vernon’s making great catches. Delanie’s making great catches. Teddy (Ginn) is making great catches. … I’m making great catches. Who else can I name?”

How about cornerbacks Carlos Rogers, who had a 31-yard interception return that gave the 49ers a 14-3 second-quarter lead, and Chris Culliver, who had his first career pick?

The two were part of a defense that allowed 272 yards and flummoxed quarterback Josh Freeman. Nine of Tampa Bay’s 11 drives finished with a punt or a turnover.

The complete victory raises the obvious question: Are the 49ers really this good?

Davis, rarely at a loss for words, didn’t hesitate when asked the question.